American mass-produced fruits are in general disgusting. They are tasteless and watery. Strawberries are probably the worst offenders. In Ukraine, strawberries are very sweet and much smaller. The American strawberries just seem full of water.
On a less jokey note, I have found myself wondering how much gene engineering it would take to fix the mismatch between size and flavor.
Typically the fruit of the plant contains a lot of chemical energy in the form of sugars. Plants that have been selectively bred for hardiness (thicker skin, longer ripening periods, etc.) expend more on those traits as opposed to making more chemical energy in the fruit.
But I sort of get a kick out of imagining a meta-physical level of "flavor per fruit" out there in the world.
Incidentally, part of what I wonder about gene engineering is whether we could keep most of the hardiness, etc, and focus very tightly on putting in more flavor compounds, instead of using the blunt stick of breeding and getting who knows what other characteristics correlated in with that. Of course it won't be free to the plant but we might still have some room for optimizing.
But if you go to a farmers market or a fruit stand, changes are you are getting fruit from local farms. At least this is the case where I live.
Also there are tons of varieties of Strawberries perhaps the ones where you live are different. Fragaria vesca looks like a strain popular around Europe that looks very different from the American variety.
Basically what I'm getting at is that American fruit that's taken care of on the way to your mouth is great. If your local fruit tastes like this, then it's just not good fruit.
When it comes to tropical fruits it is the same: American bananas taste like Styrofoam, guavas are bland.
Another such exception is avocados: http://en.wikipedia.org/wiki/Avocado#Harvest_and_postharvest (second paragraph under Harvest and Postharvest)